darktable – How to Check the Lensfun Version on Fedora

I just wanted to create calibration files for my Tamron 90mm SP, but according to LensFun, it was added in 1.613 (there is only a SP 90mm and it's the same as the one I have in EXIF). How can I check which version I have on my Fedora? And possibly how to update Lensfun library?

I want this for Darktable, which I think uses a Lens Fun database (according to the Lensfun website). However, the lens with calibration module is not recognized.

Workflow and color spaces in Darktable and GIMP for printing images?

I've started to print some of my photos, but this has led me on a path where I do not know if I'm doing things right, and I'm asked questions that I do not know the answers to. Here goes:

  • I use Ubuntu (18.04), Darktable (2.6) and Gimp (2.10).
  • My photos are taken in "Adobe RGB" color space. I have this option set in both cameras.
  • With Agryll I color-calibrated my monitor with a Spyder 4 Elite. Agryll's profile is installed system-wide. (On my desktop I choose Settings -> Devices -> Color and see the profile installed for my monitor.)
  • When I edit an image that I want to print, I choose "Adobe RGB" under "Output Color Profile" in Darktable.
  • When I export the image from Darktable, I choose TIFF, 16 bit and "Adobe RGB" as profile.
  • When I import the images into Gimp, Gimp asks me if I want to convert the images to sRGB. I say no, because Adobe RGB is better.
  • After my work is over, I save the image again as a TIFF and take it to where I want to print it.
  • The reason I want to save it as TIFF, 16 bit, and Adobe RGB is because the image contains more color and more information because the person (s) who print the image (in collaboration with) often work in the picture executes me) to do it exactly right.

My questions are:

  1. I do not need to install a profile for my monitor in Gimp or Darktable because both Gimp and Darktable (by default) use the system-wide profile. Without having to make a setting in Gimp / Darktable?
  2. Is the above workflow with 16-bit TIFF and "Adobe RGB" the right way to get as much information as possible in the picture on the go?
  3. Why does Gimp ask me when opening the TIFF file in Gimp, whether I want to convert from a built-in profile to "sRGB"? My understanding is that "Adobe RGB" is better?
  4. Is there something I should keep in mind that I did not mention? Or am I missing something? How should I set or check Darktable / Gimp?

export – Darktable loses the desired details to the night sky when exporting in JPEG

I did some night sky photos and played around in Darktable (Windows) to make the stars burst. The problem is that the exported JPEG fades out the stars, though I export with 100% quality.

Taking a screenshot (window + print screen) of the raw image in Darktable looks like this:
Enter image description here

However, the exported JPEG from Darktable looks like this:


Is there any advice on how to get the bright points when exporting?

Edit: Prompted by the user to save a PNG. I have stored in PNG with 8bit and compression to 0:
Enter image description here

Distortion – lens correction in the Darktable if my lens is unknown?

Unfortunately, darktable currently has no very good working method ad hoc Distortion correction for a lens for which you do not have a lensfuss profile. The following is a dirty hack that can useful in cases where the running distortion at the wide end of a zoom is so strong that even a "wrong" correction could be an improvement …

In the lens correction module:

  • Click the top drop-down list (Camera) and select Generic -> Crop factor 1.0 (full screen)
  • For the lens dropdown: select Generic -> Straight 10-1000 mm 1: 1.0,
  • Change that geometry to fish eye
  • change mode to distort

Now if you change the value in the "mm" drop-down menu, you should get different degrees of generic "defishing". Start with the largest mm values ​​and work the list down until you find something that seems the most likely to correct. Clicking the circular arrow button to the right of the Scale slider automatically adjusts the scale to fit the largest section without blank pixels.

If you try to correct pincushion distortion at the long end of a zoom, change the mode to "Fix" instead of "Distort".

raw – Postprocessing of Sony ARW with Darktable

I have the feeling that the ARW post-processing with Darktable leads to strange results. I tried:

  1. the "standard" base curve
  2. Base curve with two or three exposures Fusion [1]
  3. Base curve off and instead movie module [2]

Regardless of what I do, the resulting image I view with "Image Viewer" is much darker (saturated?) And flatter than in DT if I get the desired effect on the screen when converting the file to JPEG.

[1]: See https://www.darktable.org/2016/08/compressing-dynamic-range-with-exposure-fusion/

[2]: See https://www.darktable.org/2018/12/darktable-26/

lightroom – Is it legal to download Darktable in European countries?

Usually when the officially The website of each software contains download links. The download is legal. This includes proprietary software (eg updates and trial versions), provided you comply with the license terms.

There have been exceptions in the past. If you have any concerns, you should contact the developers directly.

darktable – How to export with all my CPU cores / GPU

I use draktable and it takes a long time to export all my images. Something like a few hours since there are many pictures. As I monitor my CPU usage, I see that Darktable is using all CPU cores for its GUI. However, only one kernel is used during the export. Can I ask Darktable to use all my CPU cores?

Here are the versions I use:

Darktable: 2.4.2
OS: Kubuntu 18.04

Here is a screenshot of my darktable configuration:

Enter image description here

Incidentally, I also have a GeForce GTX 1080 ti. But it is not used at all while I export images!

+ ------------------------------------------------- ---------------------------- +
| NVIDIA-SMI 396.54 driver version: 396.54 |
| ------------------------------- + ----------------- - ---- + ---------------------- +
| GPU Name Persistence M | Bus ID Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr: Use / Cap | Memory usage | GPU-Util Compute M. |
| ====================================== === == + =====================
| 0 GeForce GTX 108 ... Off | 00000000: 01: 00.0 On | N / A |
| 13% 55C P2 79W / 280W | 726 MB / 11175 MB | 3% standard |
+ ------------------------------- + ----------------- ----- + ---------------------- +

timelapse – How do I create a smooth transition between styles in fast motion with Darktable?

I enjoy making timelapses and using color correcting. The problem I have is that I would like to use a different formula in Darktable for scenes like a sunset, where the beginning and the end of the time lapse are of different exposure and color.

This causes a problem because at least two sets of images of different styles are applied thereto. Such a setting results in a jump from one color correction to the next as the timelapse images are converted to video. What I think is the right approach is to ask Darktable to move from one style to the other, from the beginning of the image list to the end.

Is there a way to do this with Darktable? What are my solutions in general?

Darktable darkens images automatically and can not be reset

Normally, I export 100% quality JPEG files from Photoshop, import the JPEG files into Darktable, and then execute watermarks, etc., before exporting them back to JPEG files with about 70% quality.

When I import a file in Darktable 2.6.2, it automatically darkens. Example below

Enter image description here

Darktable preview on the left, original JPEG image in 100% quality right.

In darktable, I have not assigned a module to the image. I just open the picture and have darkened the picture.

I checked the history stack. There was nothing applied. But something was applied with force that I can not turn off.

What's happening? Is it a bug or something?

I reset Darktable (deleted rm ~ / .config / darktable / * After reloading and importing a file, the image automatically darkens.